Counting Loops in Polymers to Improve Properties

Polymers surround us as they are used in our phones, computers, and even our clothes and cars. These materials are made of chains of molecules that bind together into a larger structure, but sometimes these bonds are not perfect. Researchers at MIT have developed a method to find and count these imperfections, which should lead to improved manufacturing techniques that will enhance polymers' properties.

You can envision the chains of molecules in a polymer as a mess of cables, all tangled up, but in this case the tangling is not a bad thing. The imperfections are actually from molecules that bind to themselves instead of others, so they are not part of the larger network. We have known since the 1940s that this weakens the polymer but without a way to count them, we have been unable to purposefully remove them. How the MIT researchers are finding these imperfections is by adding break points to the molecular chains, and then breaking them. This process produces other chemicals which can be measured to determine how many loops were in the polymer.

When the researchers were testing this they found that for some polymers the loops accounted for as little as 9% or as high as almost 100%, making the polymer's properties almost non-existent. These amounts are determined by many factors when the polymer is produced, but now that they can be quantified, manufacturing can be improved to remove the loops, and return that lost potential.